<!DOCTYPE html>
<html>

<head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
    <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.bundle.min.js"></script> </head>

<body class="container">
    <br/>
    <br/>
    <button type="button" class="btn btn-secondary" data-toggle="tooltip"
        data-placement="top" title="Tooltip on top">
        Tooltip on top
    </button>
    <button type="button" class="btn btn-secondary" data-toggle="tooltip"
        data-placement="right" title="Tooltip on right">
        Tooltip on right
    </button>
    <button type="button" class="btn btn-secondary" data-toggle="tooltip"
        data-placement="bottom" title="Tooltip on bottom">
        Tooltip on bottom
    </button>
    <button type="button" class="btn btn-secondary" data-toggle="tooltip"
        data-placement="left" title="Tooltip on left">
        Tooltip on left
    </button>
    <script>
        $(document).ready(function () {
            $('[data-toggle="tooltip"]').tooltip();
        });
    </script>

    <br/><br/><br/>
    <button type="button" class="btn btn-secondary" data-toggle="tooltip"
        data-html="true" title="<em>Tooltip</em> <u>with</u> <b>HTML</b>">
        Tooltip with HTML
    </button>
</body>

</html>